Supremacy \Su*prem"a*cy\, n. [Cf. F. supr['e]matie. See Supreme.]

The state of being supreme, or in the highest station of power; highest or supreme authority or power; as, the supremacy of a king or a parliament.

The usurped power of the pope being destroyed, the crown was restored to its supremacy over spiritual men and causes. --Blackstone.

Oath supremacy, an oath which acknowledges the supremacy of the sovereign in spiritual affairs, and renounced or abjures the supremacy of the pope in ecclesiastical or temporal affairs. [Eng.]

--Brande & C.

Source: Webster's Revised Unabridged Dictionary (1913)